Risk of malignancy in a high-incidence population-based cohort of Faroese patients with inflammatory bowel disease from 1960 to 2020 – a Faroese IBD cohort study

Abstract

Background

The association between inflammatory bowel disease (IBD) and malignancy remains disputed despite many observational studies. The Faroese population exhibits the highest occurrence of IBD in the world. This study aimed to investigate the cancer risk in Faroese IBD patients in a nationwide IBD cohort.

Methods

This study included all IBD patients diagnosed in the Faroe Islands between 1960 and 2020. Clinical demographics and cancer diagnoses were retrieved from patient files and the Faroese cancer registry. Cancer risk in IBD patients was calculated as standardized incidence ratios (SIRs) based on the Faroese background population’s age- and sex-specific cancer incidence rates, retrievable from NORDCAN.

Results

The cohort consisted of 699 patients with a total follow-up time of 9,629 person-years. Overall, the risk of cancer was not statistically significantly increased compared to the background population. Patients diagnosed with cancer at age 50–59 years had higher overall cancer risk (SIR 1.8; 95% CI, 1.02–2.99) as did UC patients diagnosed with IBD at 50–59 (SIR 2.1; 95% CI, 1.10–3.54). Absolute numbers were small and no estimates for site-specific cancers reached statistical significance, though lung, breast, and cancer of the female reproductive organs were elevated among IBD and UC patients, and colorectal cancer in CD patients.

Conclusions

This nationwide study found no statistically significantly increased risk of cancer among Faroese patients with CD or UC, except from age 50 to 59 years. While the incidence of IBD is significantly higher in the Faroe Islands than in other countries, risk estimates of cancers are comparable.

Keywords:

• Inflammatory bowel disease
• ulcerative colitis
• crohn’s disease
• malignancy
• faroe islands

Authors’ contribution

All authors have made significant contributions to the research described in this manuscript. JM, AGV, JB and KRN planned and designed the study. JM carried out the study, collected and analyzed data and drafted the manuscript. SL and TH analyzed the data. KRN scrutinized original patient files for diagnostic criteria. All authors interpreted and reviewed the manuscript critically and revised the draft of the manuscript. All authors have read and approved the final manuscript.

Disclosure statement

JB reports grants and personal fees from AbbVie, grants and personal fees from Janssen-Cilag, personal fees from Celgene, grants and personal fees from MSD, personal fees from Pfizer, grants and personal fees from Takeda, grants and personal fees from Tillots Pharma, personal fees from Samsung Bioepis, grants and personal fees from Bristol Myers Squibb, grants from Novo Nordisk, personal fees from Pharmacosmos, personal fees from Ferring, personal fees from Galapagos - none of which are related to the submitted work. The remaining authors have no conflicts of interest to declare.

Data availability statement

The main data were presented in the article and are available upon request.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the Faroese Research Council, Torben & Alice Frimodts Foundation, Aage & Johanne Louis-Hansens Foundation, the Faroese Foundation, and the Betri Foundation (to TH).